FIG. 8 is a diagram of a sample component detecting apparatus disclosed in Japanese Patent Application Publication No. 2005-300292. As shown in the figure, a module(s) 201, in which a sample is injected, is held on a disk 202 of the apparatus, and a centrifugal drive mechanism 203 rotates the disk 202, which applies a centrifugal force, and then a light source 204 irradiates, with light, the sample obtained as a result therefrom, so that an optical detection unit 205 detects fluorescence emitted from the sample. Furthermore, Japanese Patent Application Publication No. 2005-300292 discloses that it is possible to offer a sample component detecting apparatus which does not affect a measurement result even in an abnormal condition, such as dust adhering to a microarray.
However, in such an inspection apparatus using a chip disclosed in Japanese Patent Application Publication No. 2005-300292, while the module(s) 201, in which the sample is injected, is held on the disk 202, it is necessary to rotate the disk 202 at a high speed in order to apply a large centrifugal force to the disk 202. Consequently, since impurities, such as dirt and dusts, soar inside the apparatus, there is a possibility that the impurities may adhere to components of an optical component unit 206. When the impurities adhere to the components of the optical component unit 206 and are illuminated with the light from the light source 204 and the light from the sample there is a problem that measurement accuracy is deteriorated.
Detailed description of the problem will be given below. First, (1) when an absorptiometry method is used to detect a sample light from a light source passes through the sample and an optical power detector detects the light intensity. In such a case, the degree of light absorbed in the sample is judged from a light intensity difference between the light intensity of the light source and that of a light detector. However, when impurities adhere to the optical components, the light detector cannot distinguish between the light intensity drop due to absorption of the light intensity in the sample or the light intensity thereof drops since the light is blocked by the impurities, so that a correct measurement result cannot be obtained. Moreover, (2) when a fluorescence measuring method is used to detect a sample, the sample is irradiated with light from a light source, so that the sample is excited to emit fluorescence, so that the fluorescence is detected by the light detector. However, when the impurities adhere to the optical components, the impurities are irradiated with the light, so that the fluorescence is also emitted from the impurities. In this case, the light detector cannot judge whether or not the fluorescence is emitted from the sample or the impurities. Thus, the correct measurement result may not be obtained.
In view of the above-mentioned problems, it is an object of the present invention to offer an inspection apparatus using a chip, in which adhesion of impurities to optical components such as a light measurement unit for detecting a sample is suppressed.